1. Field of the Invention
The present invention relates to an output gear-equipped reduction device and a method of assembling the same.
2. Description of Related Art
Japanese Unexamined Patent Application Publication No. 2006-283983 discloses an output gear-equipped reduction device including a casing, a reduction mechanism housed within the casing, an output flange for taking out rotation reduced by a reduction mechanism, an output shaft provided on the output flange and having a smaller diameter than the output flange, and an output gear (output pinion) provided on the output shaft and having an addendum circle greater than the diameter of the output shaft. This kind of output gear-equipped reduction device is widely used, for example, for driving of turning devices in construction machinery, such as diggers.
The output gear-equipped reduction device disclosed in Japanese Unexamined Patent Application Publication No. 2006-283983 is shown in FIGS. 26 and 27. This output gear-equipped reduction device 10 includes an input shaft 12, a first pinion 14, a gear 16, and four eccentric shafts 18 which rotate via a second pinion 17, and is configured such that external gears 22A and 22B eccentrically oscillate on the radial inside of an internal gear 24 by eccentric bodies 20A and 20B provided on eccentric shafts 18, respectively.
A pair of first and second carriers 26A and 26B which takes out rotation components of the external gears 22A and 22B is arranged on both axial sides of the external gears 22A and 22B and is integrated by bolts 27. Among them, the second carrier 26B functions as an output flange so that power is transmitted to the output shaft 28 as it is. A “lump” of the first and second carrier 26A and 26B and the output shaft 28 is rotatably supported on a casing 36 by an angular contact ball bearing 32 and a taper roller bearing 34.
The output shaft 28 is mounted with an output gear (output pinion) 38 via a spline 40. This output gear 38 is a large gear which has an addendum circle having a greater diameter d2 than the external diameter d1 of the output shaft 28 and which has a face width L1 of ½ or more of the external diameter d1 of the output shaft 28.
Although the output gear-equipped reduction device 10 which has such an output gear 38 is frequently used for turning driving devices, etc. of diggers and wind turbine generator facilities as mentioned above, a very powerful radial load or thrust load may be applied to the output gear 38 by the nature of the reduction device. The output gear 38 has a face width L1 of ½ or more of the external diameter d1 of the output shaft 30 in order to cope with this powerful load in the radial direction.
Additionally, the regulation of axial movement the output gear 38 to the output shaft 28 is performed by the following configurations so as to cope with this powerful load in the thrust direction. That is, the output gear 38 is formed with stepped portions 38A and 38B. A locking ring 42 which engages with one stepped portion 38A is fitted until the locking ring comes into contact with on a stepped portion 28A formed in the output shaft 28. The locking ring 42 function as a member which specifies the axial positions of three of the output shafts 28, the taper roller bearing 34, and the output gear 38. Moreover, a locking plate 44 which engages with the other stepped portion 38B of the output gear 38 is fixed to the output shaft 28 via bolts 46. Axial movement of the output gear 38 is constrained with respect to the output shaft 28 as the output gear is sandwiched from both axial sides by the locking plate 44 and the locking ring 42.
However, in the related-art structure, in order to reliably fix to the output shaft 28 the output gear 38 to which powerful radial power load or thrust power load is applied, much time and effort, such as fitting the locking ring 42 into the output shaft 28 and fixing the locking plate 44 to the output shaft 28 via bolts 46, and many accessories were required.
Additionally, although the output shaft 28, the taper roller bearing 34, the casing 36, the output gear 38, the locking ring 42, and the locking plate 44 are respectively separate members, there is a problem in that these members are assembled in axial positions which are mutually specified, and substantial time is also taken for shim adjustment, etc. during assembling.
Moreover, in order to secure required strength, there is also a problem in that it is necessary to use large-sized parts which have respective appropriate strength for accessory members, such as the locking ring 42, the locking plate 44, and the bolts 46 for such fixation, and the whole weight is also apt to become heavy.